Directed evolution methods for overcoming trade‐offs between protein activity and stability

Engineered proteins are being widely developed and employed in applications ranging from enzyme catalysts to therapeutic antibodies. Directed evolution, an iterative experimental process composed of mutagenesis and library screening, is a powerful technique for enhancing existing protein activities and generating entirely new ones not observed in nature. However, the process of accumulating mutations for enhanced protein activity requires chemical and structural changes that are often destabilizing, and low protein stability is a significant barrier to achieving large enhancements in activity during multiple rounds of directed evolution. Here we highlight advances in understanding the origins of protein activity/stability trade‐offs for two important classes of proteins (enzymes and antibodies) as well as innovative experimental and computational methods for overcoming such trade‐offs. These advances hold great potential for improving the generation of highly active and stable proteins that are needed to address key challenges related to human health, energy and the environment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154495/1/aic16814_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154495/2/aic16814.pd

Iron deficiency reduces synapse formation in the Drosophila clock circuit

Iron serves as a critical cofactor for proteins involved in a host of biological processes. In most animals, dietary iron is absorbed in enterocytes and then disseminated for use in other tissues in the body. The brain is particularly dependent on iron. Altered iron status correlates with disorders ranging from cognitive dysfunction to disruptions in circadian activity. The exact role iron plays in producing these neurological defects, however, remains unclear. Invertebrates provide an attractive model to study the effects of iron on neuronal development since many of the genes involved in iron metabolism are conserved, and the organisms are amenable to genetic and cytological techniques. We have examined synapse growth specifically under conditions of iron deficiency in the Drosophila circadian clock circuit. We show that projections of the small ventrolateral clock neurons to the protocerebrum of the adult Drosophila brain are significantly reduced upon chelation of iron from the diet. This growth defect persists even when iron is restored to the diet. Genetic neuronal knockdown of ferritin 1 or ferritin 2, critical components of iron storage and transport, does not affect synapse growth in these cells. Together, these data indicate that dietary iron is necessary for central brain synapse formation in the fly and further validate the use of this model to study the function of iron homeostasis on brain development

Persistent non-solar forcing of Holocene storm dynamics in coastal sedimentary archives

Considerable climatic variability on decadal to millennial timescales has been documented for the past 11,500 years of interglacial climate. This variability has been particularly pronounced at a frequency of about 1,500 years, with repeated cold intervals in the North Atlantic. However, there is growing evidence that these oscillations originate from a cluster of different spectral signatures, ranging from a 2,500-year cycle throughout the period to a 1,000-year cycle during the earliest millennia. Here we present a reappraisal of high-energy estuarine and coastal sedimentary records from the southern coast of the English Channel, and report evidence for five distinct periods during the Holocene when storminess was enhanced during the past 6,500 years.We find that high storm activity occurred periodically with a frequency of about 1,500 years, closely related to cold and windy periods diagnosed earlier. We show that millennial-scale storm extremes in northern Europe are phase-locked with the period of internal ocean variability in the North Atlantic of about 1,500 years. However, no consistent correlation emerges between spectral maxima in records of storminess and solar irradiation. We conclude that solar activity changes are unlikely to be a primary forcing mechanism of millennial-scale variability in storminess

Moving towards the implementation of pharmacogenetic testing in Quebec

Clinical implementation of pharmacogenetics (PGx) into routine care will elevate the current paradigm of treatment decisions. However, while PGx tests are increasingly becoming reliable and affordable, several barriers have limited their widespread usage in Canada. Globally, over ninety successful PGx implementors can serve as models. The purpose of this paper is to outline the PGx implementation barriers documented in Quebec (Canada) to suggest efficient solutions based on existing PGx clinics and propose an adapted clinical implementation model. We conclude that the province of Quebec is ready to implement PGx

Sensitive detection of glucagon aggregation using amyloid fibril‐specific antibodies

Sensitive detection of protein aggregates is important for evaluating the quality of biopharmaceuticals and detecting misfolded proteins in several neurodegenerative diseases. However, it is challenging to detect extremely low concentrations (20 times more sensitive than detection using a conventional, amyloid‐specific fluorescent dye (Thioflavin T). We expect that this type of sensitive immunoassay can be readily integrated into the drug development process to improve the generation of safe and potent peptide therapeutics.Sensitive detection of protein aggregates is important for evaluating the quality of biopharmaceuticals and detecting misfolded proteins in several neurodegenerative diseases. However, it is challenging to detect extremely low concentrations (20 times more sensitive than conventional methods for detecting glucagon fibrils.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150615/1/bit26994_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150615/2/bit26994.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150615/3/bit26994-sup-0001-Supporting_Information__submission_.pd

La carrière Saingt à Fleury-sur-Orne

Depuis 2014, la carrière Saingt, l’une des nombreuses carrières-refuges utilisées par les civils pris sous les bombes lors de la Bataille de Caen (juin-juillet 1944), offre l’opportunité de mettre en place une opération archéologique à caractère expérimental permettant de confronter différents types d’analyses, au croisement de l’archéologie, de l’histoire et de la sociologie. Ce programme de recherche, débuté en 2015, associe des chercheurs de l’Inrap, du CNRS, de l’INSA-Strasbourg et des sp..

Ten golden rules for optimal antibiotic use in hospital settings: the WARNING call to action

Antibiotics are recognized widely for their benefits when used appropriately. However, they are often used inappropriately despite the importance of responsible use within good clinical practice. Effective antibiotic treatment is an essential component of universal healthcare, and it is a global responsibility to ensure appropriate use. Currently, pharmaceutical companies have little incentive to develop new antibiotics due to scientific, regulatory, and financial barriers, further emphasizing the importance of appropriate antibiotic use. To address this issue, the Global Alliance for Infections in Surgery established an international multidisciplinary task force of 295 experts from 115 countries with different backgrounds. The task force developed a position statement called WARNING (Worldwide Antimicrobial Resistance National/International Network Group) aimed at raising awareness of antimicrobial resistance and improving antibiotic prescribing practices worldwide. The statement outlined is 10 axioms, or “golden rules,” for the appropriate use of antibiotics that all healthcare workers should consistently adhere in clinical practice

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Editorial ISNT 2023

National audienc

Diarrhoea with the angiotensin receptor neprilysin inhibitor sacubitril + valsartan: A pharmacovigilance study

International audienceDiarrhoea is an adverse drug reaction of the angiotensin receptor neprilysin inhibitor (ARNI) sacubitril + valsartan. It was also described with olmesartan and more recently with other angiotensin receptor blockers. The study was performed to compare diarrhoea reports in pharmacovigilance databases with sacubitril + valsartan and valsartan. The study used reports of diarrhoea with the ARNI sacubitril + valsartan registered: first in the French PharmacoVigilance Database (FPVD) and second in Vigibase®, the WHO Global Individual Case Safety Report database. After description of the main characteristics, disproportionality analyses were performed. Results are reported as reporting odds ratios (ROR) with 95% confidence interval. We found 29 reports of diarrhoea with sacubitril + valsartan in the FPVD and 686 in Vigibase®. With sacubitril + valsartan, diarrhoea occurred more frequently in males around 70 years with a median delay of 3 days. With valsartan, diarrhoea occurred more frequently in females around 68 years with a median delay of 0.5 days. In the FPVD, a significant association was found with sacubitril + valsartan in comparison with valsartan alone before (ROR = 8.78 [5.19–14.85]) and after (ROR = 11.19 [5.89–21.25]) exclusion of concomitant drugs known to be associated with diarrhoea. A significant association was also found in Vigibase® after adjustment on age, sex, reporter and its location (ROR = 1.31 [1.14–1.50]). Diarrhoea reported with sacubitril + valsartan has marked differences in gender, delay of occurrence and frequency of reporting in comparison with diarrhoea with valsartan. From a pharmacodynamic point of view, these results suggest a specific role of sacubitril in diarrhoea